Answer:
10 sides (decagon)
Step-by-step explanation:
You find the perimeter by adding up all the sides of a shape.
side + side + side + side... = perimeter
You know that <em>each</em> side is 4/5 centimeters. You also know that the perimeter is 8 centimeters.
<u>You can set up an equation like this:</u>
4/5 * number of sides = 8
<em>or you can write it in a simpler form as:</em>
4/5x=8
<u>Now solve it like a normal equation:</u>
5 * (4/5x) = (8) * 5
(4x) / 4=(40) / 4
x = 10
So, you know the shape has 10 sides that are 4/5 centimeters each.
if the sphere has a diameter of 5, then its radius is half that, or 2.5.
![\bf \textit{volume of a sphere}\\\\ V=\cfrac{4\pi r^3}{3}~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=2.5 \end{cases}\implies V=\cfrac{4\pi (2.5)^3}{3}\implies V=\cfrac{62.5\pi }{3} \\\\\\ V\approx 65.44984694978736\implies V=\stackrel{\textit{rounded up}}{65.45}](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Bvolume%20of%20a%20sphere%7D%5C%5C%5C%5C%20V%3D%5Ccfrac%7B4%5Cpi%20r%5E3%7D%7B3%7D~~%20%5Cbegin%7Bcases%7D%20r%3Dradius%5C%5C%5B-0.5em%5D%20%5Chrulefill%5C%5C%20r%3D2.5%20%5Cend%7Bcases%7D%5Cimplies%20V%3D%5Ccfrac%7B4%5Cpi%20%282.5%29%5E3%7D%7B3%7D%5Cimplies%20V%3D%5Ccfrac%7B62.5%5Cpi%20%7D%7B3%7D%20%5C%5C%5C%5C%5C%5C%20V%5Capprox%2065.44984694978736%5Cimplies%20V%3D%5Cstackrel%7B%5Ctextit%7Brounded%20up%7D%7D%7B65.45%7D)
(9x^2 +4x -7) - x^2 +2x - 6
8x^2 +6x - 13.
Get a grip on your life son. This is really simple.
